What’s a contemporary artist to do, faced with the slick world of consumer gadgetry, which seems to slurp up so very much of the public’s attention? Alex Dodge’s show at Williamsburg’s Klaus Von Nichtssagend Gallery offers a novel answer: He turns the gallery into a space to show off his own conceptual gizmo prototypes, realized with the help of his very own, very real, tech start-up, Generative, Inc.